This renewal application of a program project seeks support for the collaborative effort of a group of investigators devoted to an integrated study of the biology of neoplasia. The investigators include surgeons, experimental pathologists, electron microscopists, biochemists and cell biologists, biophysicists and mathematicians. The interests range from clinical studies of melanoma in man to the molecular basis of cell proliferation and computer analysis of cell kinetics. The program is also intended to speed up the flow of technology from the laboratory to the clinical bed.